文献类型： 外文期刊

作者： Zou, Zhi ¹ ; Fu, Xiaowen ¹ ; Li, Chunqiang ¹ ; Huang, Jiaquan ¹ ; Zhao, Yongguo ¹ ;

作者机构： 1.Chinese Acad Trop Agr Sci, Inst Trop Biosci & Biotechnol, Natl Key Lab Trop Crop Breeding, Sanya Res Inst,Hainan Key Lab Biosafety Monitoring, Haikou 571101, Hainan, Peoples R China

2.Hainan Univ, Sanya Inst Breeding & Multiplicat, Sch Breeding & Multiplicat, Sanya 572025, Hainan, Peoples R China

3.Hainan Univ, Coll Trop Agr & Forestry, Sanya 572025, Hainan, Peoples R China

4.Guangdong Univ Petrochem Technol, Coll Biol & Food Engn, Maoming 525000, Guangdong, Peoples R China

关键词： Cyperus esculentus; Vegetative tissue; Underground tuber; FAD; Phylogenomics; Orthologous analysis; Syntenic analysis

期刊名称：BMC PLANT BIOLOGY （ 影响因子：4.8； 五年影响因子：5.4 ）

ISSN： 1471-2229

年卷期： 2025 年 25 卷 1 期

页码：

收录情况： SCI

摘要： BackgroundTigernut (Cyperus esculentus L.), an oil-rich tuber plant of the Cyperaceae family, is typical for the naturally high content of oleic acid. However, to date, genes contributing to oil composition have not been well characterized.ResultsIn this study, the first genome-wide analysis of tigernut genes encoding membrane-bound fatty acid desaturases (FADs), the key contributors to oil composition, is presented. According to phylogenetic analysis, ten members identified from the tigernut genome were assigned into seven out of eight evolutionary groups as defined in Arabidopsis thaliana, i.e., FAD2 (3), FAD6 (1), FAD3 (1), FAD7 (1), FAD4 (1), DES (1), and SLD (2). In contrast to the absence of an FAD5 homolog, FAD2 and SLD in tigernut were shown to have expanded via tandem and dispersed duplications, respectively. Comparison of 285 members from 29 representative plant species resulted in 11 orthogroups, where FAD2a, FAD6, FAD7, FAD3, FAD4, FAD5, DES, and SLD1 were shown to have already appeared in the ancestor of seed plants. Significantly, orthologous and syntenic analyses revealed that loss of FAD5 and expansion of SLD in tigernut are lineage-specific, occurred sometime before the radiation of core monocots, in contrast to species-specific expansion of FAD2. Moreover, though no syntenic relationship was observed between CeFAD genes, our comparative genomics analyses indicated that FAD3 and -7 are more likely to arise from segmental duplication. Structural variation and expression divergence of CeFAD genes were also observed. Gain of introns in CeFAD4, CeSLD1, and CeSLD2 was shown to be lineage-specific, occurred sometime before Cyperaceae-Juncaceae split. Tissue-specific expression analysis revealed that CeFAD2-1, CeFAD6, and CeFAD7 were constitutively expressed, whereas others were tissue-specific. Among five paralogs identified, CeFAD2-1 and CeSLD1 have evolved to be two dominant members. Putative roles of CeFAD2-1 in oil accumulation are supported by 1) exhibited an expression pattern positively associated with oil accumulation during tuber development; 2) were expressed more in tubers than their orthologs in C. rotundus. Additionally, in contrast to high expression of CrFAD3, transcript levels of CeFAD3 in tubers were fairly low, which may explain the distinct alpha-linolenic acid content between these two close species.ConclusionsOur findings provide a global view of CeFAD genes, which not only highlights lineage-specific evolution of the family, but also provides valuable information for further functional analysis and genetic improvement in tigernut.